Electric motors which drive mechanical shifting devices are generally used in known adjusting devices of gear shift elements in claw clutch operated automated gear boxes of vehicles. The mechanical shifting devices usually convert the rotary motion of the electric motor into a translatory motion. The gear shift elements, such as gear shift sleeves, are moved by the mechanical shifting devices. A spindle, for example, can serve as a mechanical shifting device.
A control device is responsible for controlling shifting of the gear shift element.
It is necessary for the control device to know the exact position of the shifting device and, consequently the position of the gear shift element, before shifting the gear shift element.
There are several possibilities for detecting the position of the shifting device. One possibility is to measure the translation of the shifting device absolutely via a travel sensor. However, these sensors are expensive and require a relatively large installation space. A further possibility is to equip the electric motors with known sensors to measure the direction of rotation and the engine speed. In order to enable an exact determination of the position of the shifting device, these are customarily combined with reference sensors. A reference point is selected therein in a first step and the position of the shifting device is calculated based on a movement starting from this reference point. Selection of the reference point is necessary therein, since the memory, in which the position is stored, is usually non-permanent and, in addition, the position of the gear shift element can change due to the vibration of the vehicle.
For this reason, it is the object of the invention to enable a more economical method and device for detecting the position of gear shift elements in claw clutch operated automated gear boxes.